Filter driver to enumerate smartcard nodes for plug and play

ABSTRACT

Described herein is a filter driver in a smartcardreader class that recognizes the presence of a smartcard in a smartcard reader and creates a device node (devnode).

BACKGROUND

Smartcards are portable devices that include an embedded integrated circuit. Smartcards may be passive memory devices or contain a microcontroller and associated memory for various functions. Smartcard form factors include plastic cards, fobs, subscriber identification modules (SIMs), and the like.

Applications for smartcards include payment systems, access control, identification, cryptographic controls and authentication, and telecommunications.

The current lack of automatic recognition of smartcards in current operating system plug and play frameworks renders them difficult to use and deploy. When drivers or associated software or both have not been previously installed, the smartcard is unusable and applications looking to the smartcard will fail. Manual installation is thus necessary to render the smartcard fully functional.

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

In view of the above, this disclosure describes various exemplary methods and systems for utilizing an upper-level filter driver (“filter driver”) to enumerate smartcard nodes for an operating system framework.

In an exemplary implementation, a smartcard (“card”) is inserted into a smartcard reader. Upon notification of this event, a filter driver triggers notification of a smartcard plug and play (“PnP”) service that a card has been inserted. The smartcard plug and play service then instructs the filter driver to create a device node (“devnode”). Once created, the devnode is recognized by an operating system plug and play framework and enumeration is completed.

Use of an upper-level class filter allows the seamless addition of this functionality to an existing operating system without adversely affecting legacy drivers or applications.

An exemplary system described includes a processor and a memory, and is configured to utilize a filter driver to create a devnode, which is recognized by the operating system plug and play framework.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items.

FIG. 1 shows exemplary devices utilizing a filter driver to enumerate a smartcard in an operating system.

FIG. 2 is a schematic diagram showing an exemplary system to implement a filter driver for enumerating a smartcard in an operating system.

FIG. 3 is an exemplary flow diagram of one implementation of using a filter driver to enumerate a smartcard in an operating system.

FIG. 4 is a schematic diagram of an exemplary computing system suitable as an environment for practicing aspects of the subject matter.

DETAILED DESCRIPTION

FIG. 1 shows exemplary devices 100 which may utilize a filter driver to enumerate a smartcard in an operating system. These devices may include, but are not limited to, a laptop computer 102, a cellular phone 104, a desktop computer 106, an automated teller machine (ATM) 108 or point of sale device, a personal digital assistant (PDA) 110, and the like. It is understood that devices utilizing an operating system implementing a filter driver and a smartcard or subscriber information module (SIM) may incorporate, at least in part, the techniques described herein.

FIG. 2 is a schematic diagram 200 showing an exemplary system implementing a filter driver for enumerating a smartcard in an operating system. Depicted is an operating system 202. Exemplary operating systems include, but are not limited to, members of the Microsoft Windows™ family including Windows 2000™, Windows XP™, Windows Vista™, Windows Mobile®, as well as other operating system families including Linux and its derivatives, Mac OS™, AIX™, and the like.

Within operating system 202 is a class framework 204, which provides a hierarchy of component objects. The class framework provides for various classes of objects present in the system including monitors, human interface devices, networks adapters, smartcards, and the like.

Within the class framework 204 is a smartcardreader class 206. In keeping with the class framework hierarchy, properly enumerated smartcards manifest under the smartcardreader class 206.

Within the smartcardreader class 206 is an upper-level filter driver 208, typically operating in kernel mode. An upper-level filter driver (“filter driver”) is a driver that modifies and extends the behavior of subordinate objects. Because a filter driver provides this ability to modify behavior of subordinate objects while continuing to pass through commands, it is an ideal way to seamlessly add functionality without affecting legacy software.

The upper-level filter driver 208 encompasses card reader driver 210. Therefore, in the exemplary system, the filter driver 208 modifies the behavior of the subordinate card reader driver 210 and its subordinates. However, no modification to card reader driver 210 or the card reader driver's subordinates takes place.

Within card reader driver 210 is a card specific device node (“devnode”) function driver 212. A devnode is an operating system internal structure that represents a device on a computer system. The card specific devnode function driver 212 enables the full functionality of a specific smartcard 214 within the operating system 202.

Within operating system 202 is also a smartcard service 216, which manages the smartcard resources. In Microsoft Windows™ an example of a smartcard service is the SCardSvr service which may run inside a SVCHost, also known as a smartcard resource manager. The smartcard service provides the basic infrastructure utilized by other smartcard components, and manages a smartcard reader on a system and its application interactions. Within Microsoft Windows™, the smartcard resource manager (also abbreviated “SCRM”) may be implemented as a shared service running in the context of a Local Service.

Also within operating system 202 is a smartcard plug and play service 218. The smartcard plug and play service may operate in a user mode and is responsible for managing and communicating with the filter driver to create the devnode for the smart card.

Within operating system 202 is also the operating system plug and play framework 220 which detects a devnode, and may also install appropriate driver, or application software, or both, necessary to render the smartcard fully functional.

A third party update 222 is also present in the operating system, which works in conjunction with the operating system plug and play framework 220 to communicate to a third-party 224 via a communication link to retrieve appropriate drivers, or application software, or both, necessary for the card to function properly. One example includes, but is not limited to, the Microsoft™ Windows™ Update. Microsoft™ Windows™ Update is a service which enables users to connect to a source (typically centralized and trusted) and download compliant drivers, or support software, or both, necessary to enable full plug and play functionality of installed devices with minimal user intervention.

Finally, the operating system 202 and its components, both inherent and those specified above, may communicate with the smartcard application 226. Smartcard applications may include displaying available balance information in a stored-value smartcard, storing or retrieving medical data to the card, and the like. Alternatively, the smartcard application 226 may be present within operating system 202 as an operating system component, such as a cryptographic service provider (CSP), or have components present both within the operating system as well as in an application space.

FIG. 3 is an exemplary flow diagram of one implementation of using a filter driver to enumerate a smartcard in an operating system 300. For simplicity, the process will be described with reference to the exemplary computer system 200 described above with reference to FIG. 2. Although specific details of exemplary method are described below, it should be understood that certain acts need not be performed in the order described, and may be modified, or may be omitted entirely, or both, depending on the circumstances. Moreover, the acts described may be implemented by a computer, processor or other computing device based on instructions stored on one or more computer-readable storage media. The computer-readable storage media may be any available media that may be accessed by a computing device to implement the instructions stored thereon.

At 302, a card reader driver 210 notifies a filter driver 208 of an insertion event. An insertion event may be the actual physical insertion of a smartcard, establishing a connection between a smartcard and a smartcard reader via a wireless connection (wireless including, but not limited to, infrared and radio frequency), or remotely through redirection at a remote terminal, or re-discovery of a smartcard in a reader following simulated removal.

At 304, the filter driver 208 notifies the smartcard service 216 of the insertion event.

At 306, the smartcard service 216 notifies the smartcard plug and play service 218 of the insertion.

At 308, the smartcard plug and play service 218 notifies the filter driver 208 to create a devnode.

At 310, the filter driver 208 creates the devnode.

At 312, the devnode is detected by the operating system plug and play framework 220.

At 314, a determination is made as to whether the smartcard has been previously installed. When the smartcard has been previously installed, at 316, the operating system plug and play framework 220 enumerates the smartcard devnode, and the smartcard is now fully installed.

When the card has not been previously installed, at 318, the operating system plug and play framework 220 installs the software enabling the devnode to be fully functional. This installation may utilize a third-party update 222, for example Windows Update, which then may search for the necessary installation files either locally or at a remote third party 224. Proceeding to 316, the operating system plug and play framework 220 completes the enumeration of the smartcard devnode. The smartcard is now fully installed.

Another embodiment places the functionality to create a devnode at the reader driver, rather than at the filter driver as described above.

FIG. 4 shows an exemplary computing system 400 suitable as an environment for practicing aspects of the subject matter, for example to host an exemplary operating system 202. The components of computing system 400 may include, but are not limited to, a processing unit 406, a system memory 430, and a system bus 421 that couples various system components including the system memory 430 and the processing unit 406. The system bus 421 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, Peripheral Component Interconnect (PCI) bus also known as the Mezzanine bus, Serial Advanced Technology Attachment (SATA), PCI Express, Hypertransport™, and Infiniband.

Exemplary computing system 400 typically includes a variety of computing device-readable storage media. Computing device-readable storage media may be any available media that can be accessed by computing system 400 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computing device-readable media may comprise computing device storage media and communication media. Computing device storage media include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computing device-readable instructions, data structures, program modules, or other data. Computing device storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other computer readable storage medium which can be used to store the desired information and which can be accessed by computing system 400. Communication media typically embodies computing device-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computing device readable media.

The system memory 430 includes or is associated with computing device storage media in the form of volatile or nonvolatile memory such as read only memory (ROM) 431 and random access memory (RAM), or both. A basic input/output system 433 (BIOS), containing the basic routines that help to transfer information between elements within computing system 400, such as during start-up, is typically stored in ROM 431. RAM system memory 430 typically contains data or program modules or both that are immediately accessible to or presently being operated or both on by processing unit 406. By way of example, and not limitation, FIG. 4 illustrates operating system 435, application programs 434, other program modules 436, and program data 437. Although the exemplary operating system 202 is depicted as software in random access memory 430, other implementations of an operating system 202 can be hardware or combinations of software and hardware.

The exemplary computing system 400 may also include other removable/non-removable, volatile/nonvolatile computing device storage media. By way of example only, FIG. 4 illustrates a hard disk drive 441 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 451 that reads from or writes to a removable, nonvolatile magnetic disk 452, and an optical disk drive 455 that reads from or writes to a removable, nonvolatile optical disk 456 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computing device storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 441 is typically connected to the system bus 421 through a non-removable memory interface such as interface 440, and magnetic disk drive 451 and optical disk drive 455 are typically connected to the system bus 421 by a removable memory interface such as interface 450.

The drives and their associated computing device storage media discussed above and illustrated in FIG. 4 provide storage of computing device-readable instructions, data structures, program modules, and other data for computing system 400. In FIG. 4, for example, hard disk drive 441 is illustrated as storing operating system 444, application programs 1545, other program modules 446, and program data 447. Note that these components can either be the same as or different from operating system 435, application programs 434, other program modules 436, and program data 437. Operating system 444, application programs 445, other program modules 446, and program data 447 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the exemplary computing system 400 through input devices such as a keyboard 448 and pointing device 461, commonly referred to as a mouse, trackball, or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 406 through a user input interface 460 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port, or a universal serial bus (USB). A monitor 462 or other type of display device is also connected to the system bus 421 via an interface, such as a video interface 490. In addition to the monitor 462, computing devices may also include other peripheral output devices such as speakers 1597 and printer 496, which may be connected through an output peripheral interface 495.

The exemplary computing system 400 may operate in a networked environment using logical connections to one or more remote computing devices, such as a remote computing device 480. The remote computing device 480 may be a personal computing device, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to computing system 400, although only a memory storage device 481 has been illustrated in FIG. 4. The logical connections depicted in FIG. 4 include a local area network (LAN) 471 and a wide area network (WAN) 473, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computing device networks, intranets, and the Internet.

When used in a LAN networking environment, the exemplary computing system 400 is connected to the LAN 471 through a network interface or adapter 470. When used in a WAN networking environment, the exemplary computing system 400 typically includes a modem 472 or other means for establishing communications over the WAN 473, such as the Internet. The modem 472, which may be internal or external, may be connected to the system bus 421 via the user input interface 460, or other appropriate mechanism. In a networked environment, program modules depicted relative to the exemplary computing system 400, or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 4 illustrates remote application programs 485 as residing on memory device 481. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computing devices may be used.

Although specific details of exemplary methods are described with regard to the figures presented herein, it should be understood that certain acts shown in the figures need not be performed in the order described, and may be modified, or may be omitted entirely, or both, depending on the circumstances. Moreover, the acts described may be implemented by a computer, processor or other computing device based on instructions stored on one or more computer-readable storage media. The computer-readable media can be any available storage media that can be accessed by a computing device to implement the instructions stored thereon.

CONCLUSION

Although exemplary systems and methods have been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claimed methods, devices, systems, etc. 

1. A method for exposing a smartcard to plug and play enumeration, the method comprising: detecting a smartcard insertion event; sending a notice of the smartcard insertion event from a reader driver to a filter driver in a smartcard class; sending a notice of the smartcard insertion event from the filter driver to a smartcard service; sending a notice of the smartcard insertion event from the smartcard service to the smartcard plug and play service; sending a notice to create a devnode from the smartcard plug and play service to the filter driver; triggering the filter driver to create the devnode; and detecting the devnode in an operating system plug and play framework.
 2. The method of claim 1 further comprising: installing software for the devnode using the operating system plug and play framework; and enumerating the devnode within a smartcard reader.
 3. The method of claim 2 further comprising: communicating with a third-party to allow automatic retrieval and installation of the software for the devnode.
 4. The method of claim 1 further comprising: enumerating the devnode when the smartcard has been previously installed.
 5. The method of claim 1 wherein the smartcard contains a cryptographic service provider component or a subscriber information module.
 6. The method of claim 1 further comprising: configuring a processor to instantiate at least one of the following: the reader driver, the filter driver, the smartcard service, or the smartcard plug and play service.
 7. The method of claim 1 further comprising: utilizing a cryptographic service provider in conjunction with the smartcard.
 8. A method comprising: instantiating a filter driver in a smartcard class; recognizing a smartcard at a smartcard reader and communicating the presence to the filter driver; and triggering the filter driver to create a devnode.
 9. The method of claim 8 wherein the filter driver passes a notification between a reader driver and a smartcard service.
 10. The method of claim 8 further comprising: enumerating the devnode within an operating system plug and play framework.
 11. The method of claim 8 further comprising: installing the smartcard using the operating system plug and play framework; and enumerating the devnode in an operating system plug and play framework.
 12. The method of claim 8 further comprising: communicating with a third-party to allow automatic retrieval and installation of the software to be installed.
 13. The method of claim 8 further comprising: configuring a processor to instantiate at least one of the following: a reader driver, the filter driver, a smartcard service, or a smartcard plug and play service.
 14. A system for smartcard enumeration, the system comprising: a processor; a memory coupled to the processor; a smartcard reader coupled to the processor and configured to establish connection with a smartcard; and a filter driver or a reader driver coupled to the smartcard reader and configured to create a devnode corresponding to the smartcard connected to the smartcard reader.
 15. The system of claim 14 further comprising: a smartcard plug and play service coupled to the filter driver and configured to trigger the filter driver to create the devnode.
 16. The system of claim 14 further comprising: an operating system plug and play framework coupled to the processor and configured to install software for the devnode when the smartcard has not been previously installed.
 17. The system of claim 14 further comprising: an operating system plug and play framework to enumerate the devnode.
 18. The system of claim 16 further comprising: a third-party update service coupled to the processor and configured to communicate with a third-party to allow automatic retrieval and installation of the software.
 19. The system of claim 14 wherein the smartcard functions are accessible only via the smartcard reader.
 20. The system of claim 14 wherein the processor is further configured to instantiate at least one of the following: the reader driver, a smartcard service, or a smartcard plug and play service. 